Power monitoring systems monitor the flow of electrical power in circuits through a plant or other facility. In the POWERLOGIC® system manufactured by the instant assignee, Square D Company, circuit monitors and power meters are dedicated to power monitoring, while other compatible devices collect additional equipment information from protective relays, circuit breakers, transformer temperature controllers, and panelboards. Electrical data, such as current, power, energy, waveforms, and equipment status, is passed over a data network to one or more personal computers. The personal computers run power monitoring application software that retrieves, stores, organizes, and displays real-time circuit information in simple, usable formats. The information collected and stored in a power monitoring system helps operate a facility more efficiently. The quality of the data depends upon the accuracy of the instrumentation and the usability of the display formats.
The power meter can replace conventional metering devices such as ammeters, voltmeters, and watt-hour meters while providing other capabilities not offered by analog metering. The power meter's true rms readings reflect non-linear circuit loading more accurately than conventional analog metering devices. The power meter calculates the neutral current, which can assist in identifying overloaded neutrals due to either unbalanced single phase loads or harmonics. Circuits can be closely monitored for available capacity by keeping track of the peak average demand current.
Permanently installed electrical monitoring equipment is typically installed during a plant shut-down which may only happen once or twice a year. One or more metering devices are typically installed during these shutdowns. Upon re-energizing the electrical distribution equipment in the facility some wiring errors may be found that cannot be corrected until the next shut-down due to cost of taking manufacturing down to correct for these errors. In poly-phase systems, common wiring errors include swapping phases on the voltage and current channels or wiring current phases backwards. For example, the installer may mistakenly connect the phase B voltage line to the phase C voltage line on a meter. Due to the differences in electrical connectors typically used, interchanging current and voltage lines is normally not encountered.
In somewhat more sophisticated or higher-end monitoring systems, a microprocessor-based control system is utilized. In such systems, phase wiring errors may be corrected using software. However, this solution requires more microprocessor processing time as well as at least double the memory requirement. That is, buffers or registers used to take in the raw data from the metering points or monitor input would have to be duplicated by a second buffer or register, in each instance, to transfer the corrected data points under control of the processor. In lower-end metering applications, there is either insufficient processing power, insufficient memory, or both to correct phase wiring errors through software alone. Moreover, the analog circuitry which processes and digitizes the incoming signals is space-consuming.
Therefore, a need exists for a system and method for detecting and correcting wiring errors without having to shut-down the system and without burdening the processor with memory-intensive operations. A need also exists for a power-monitoring system having a reduced circuit board footprint. The present invention satisfies this and other needs.